The writer and director Cord Jefferson has struck gold with his first feature film, “American Fiction.” Nominated for five Academy Awards, including Best Picture and Best Adapted Screenplay for Jefferson, the film is winning praise for portraying a broader spectrum of the Black experience than most Hollywood movies. It’s based on the 2001 novel “Erasure,” by Percival Everett, a satire of the literary world.  And Jefferson, who began his career as a journalist before branching out into entertainment, has long seen up close how rigid attitudes about what constitutes “Blackness” can be. “Three months before I found ‘Erasure,’ I got a note back on a script from an executive” on another script, Jefferson tells his friend Jelani Cobb, “that said, ‘We want you to make this character blacker.’ ” (He demanded that the note be explained in person, and it was quickly dropped.) Jefferson hopes that his film sheds some light on what he calls the “absurdity” of race as a construct. He finds race “a fertile target for laughter. … On the one hand, race is not real and insignificant and [on the other hand] very real and incredibly important. Sometimes life or death depends on race. And to me that inherent tension and absurdity is perfect for comedy.”